.\"	$Id$
.\"
.\" Copyright (c) 2011 Kristaps Dzonsons <kristaps@bsd.lv>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
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.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd $Mdocdate$
.Dt APROPOS 1
.Os
.Sh NAME
.Nm apropos
.Nd search manual page databases
.Sh SYNOPSIS
.Nm
.Op Fl M Ar manpath
.Op Fl m Ar manpath
.Op Fl S Ar arch
.Op Fl s Ar section
.Ar expression...
.Sh DESCRIPTION
The
.Nm
utility queries manual page databases generated by
.Xr mandocdb 8 , 
evaluating on
.Ar expression
for each file in each database.
Its arguments are as follows:
.Bl -tag -width Ds
.It Fl M Ar manpath
Use the colon-separated path instead of the default list of paths
searched for
.Xr mandocdb 8
databases.
Invalid paths, or paths without manual databases, are ignored.
.It Fl m Ar manpath
Append the colon-separated paths to the list of paths searched
for
.Xr mandocdb 8
databases.
Invalid paths, or paths without manual databases, are ignored.
.It Fl S Ar arch
Search only for a particular architecture.
.It Fl s Ar cat
Search only for a manual section.
See
.Xr man 1
for a listing of manual sections.
.El
.Pp
An
.Ar expression
consists of search terms joined by logical operators
.Fl a
.Pq and
and
.Fl o
.Pq or .
The
.Fl a
operator has precedence over
.Fl o
and both are evaluated left-to-right.
.Pp
.Bl -tag -width Ds
.It \&( Ar expr No \&)
True if the subexpression
.Ar expr
is true.
.It Ar expr1 Fl a Ar expr2
True if both
.Ar expr1
and
.Ar expr2
are true (logical
.Qq and ) .
.It Ar expr1 Oo Fl o Oc Ar expr2
True if
.Ar expr1
and/or
.Ar expr2
evaluate to true (logical
.Qq or ) .
.It Ar term
True if
.Ar term
is satisfied.
This has syntax
.Li [key[,key]*(=~)]?val ,
where operand
.Li key
is an
.Xr mdoc 7
macro to query and
.Li val
is its value.
Operator
.Li \&=
evaluates a substring, while
.Li \&~
evaluates a regular expression.
.It Fl i Ar term
Same as
.Ar term ,
but
.Ar term
is evaluated case-insensitively.
.El
.Pp
By default,
.Nm
searches for
.Xr mandocdb 8
databases in the default paths stipulated by
.Xr man 1 ,
parses terms as case-sensitive regular expressions
.Pq the Li \&~ operator
over manual names and descriptions
.Pq the Li \&Nm No and Li \&Nd No macros .
Multiple terms imply pairwise
.Fl o .
Results are sorted by manual title, with output formatted as
.Pp
.D1 title(sec) \- description
.Pp
Where
.Qq title
is the manual's title (note multiple manual names may exist for one
title),
.Qq sec
is the manual section, and
.Qq description
is the manual's short description.
If an architecture is specified for the manual, it is displayed as
.Pp
.D1 title(cat/arch) \- description
.Pp
Resulting manuals may be accessed as
.Pp
.Dl $ man \-s sec title
.Pp
If an architecture is specified in the output, use
.Pp
.Dl $ man \-s sec \-S arch title
.Sh ENVIRONMENT
.Bl -tag -width Ds
.It Ev MANPATH
Comma-separated paths overriding the default list of paths searched for
manual databases.
Invalid paths, or paths without manual databases, are ignored.
Takes precedence over
.Fl M .
.El
.\" .Sh FILES
.Sh EXIT STATUS
.Ex -std
.Sh EXAMPLES
Search for
.Qq mdoc
within the manual name and description:
.Pp
.Dl $ apropos mdoc
.Pp
Two variants of searching for
.Qq mdoc ,
.Qq roff ,
or
.Qq man
within manual names and descriptions:
.Pp
.Dl $ apropos mdoc roff man
.Dl $ apropos mdoc \-o roff \-o man
.Pp
Search for
.Qq optind
and
.Qq optarg
as variable names in the library category:
.Pp
.Dl $ apropos \-s 3 \(dqVa~^optind$\(dq -a \(dqVa~^optarg$\(dq
.Pp
Search for all manuals referencing
.Qq POSIX
in any letter case:
.Pp
.Dl $ apropos \-\- \-i posix
.Sh SEE ALSO
.Xr man 1 ,
.Xr mandoc 1 ,
.Xr re_format 7
.Sh AUTHORS
The
.Nm
utility was written by
.An Kristaps Dzonsons ,
.Mt kristaps@bsd.lv .